Targeted peptides included in the PRM method.

<p>Bold,underscored peptides were used for final quantification. C-terminal arginine (R) and Lysine (K) were heavy labeled. All cysteines are carbamidomethylated. The fragments selected for quantification are given, and all these fragments were singly charged.</p

Internal standard dilution series.

<p>QPrEST™ and NEPTune™ peptides spiked into cat serum, analyzed with the PRM method at different concentrations. The ratio synthetic/native peptide is plotted against the spiked concentration.</p

Result of shotgun analyses of gel fractionated cat sera samples.

<p>Result of shotgun analyses of gel fractionated cat sera samples.</p

Homology study of the four selected cat proteins and their human analogues.

<p>Human (*) and feline (¤) amino acid sequence with QPrEST™ sequence underscored in the human sequence. IGFBP–5 has two available QPrESTs™ while IGF–II and IGFBP–3 have one each. Tryptic peptides in QPrESTs™ matching peptides found in the feline sequence are market in bold italic (green peptides were used for quantification and the red ones were evaluated but not used). For IGF-I there was no tryptic peptide in the QPrEST™ that matched any feline peptide. The blue peptide is the synthetic NEPTune™ peptide used for quantification and the red peptide was evaluated but not used. The shorter mature protein is marked between ││ for IGF–I and IGF–II. Similarity scores from EMBOSS Needle is presented below the sequences.</p